1What is an atom?
smallest part of an element that can exist
2What is Dalton’s model of the atom?
atoms as solid spheres that could not be divided into smaller parts
3What is the plum pudding model of the atom?
sphere of positive charge with negative electrons embedded in it
4What did scientists discover in the alpha scattering experiment?
Some alpha particles were deflected by the gold foil- this showed that an atom’s mass and positive charge must be concentrated in one small space(the nucleus)
5Describe the nuclear model of the atom
dense nuclease with electrons orbiting it
6What did Neils Bohr discover?
electrons orbit in a fixed ENERGY LEVELS(shells)
7What did James Chadwick discover?
uncharged particle called the neutron
8Where are protons and neutrons?
in the nucleus
9What is the relative mass of each sub atomic particle?
proton=1. neutron=1. electron=0(very small)
10What is the relative charge for each subatomic particle?
proton=+1. neutron=0. electron=-1
11how can you find out the number of protons in an atom?
the atomic number on the periodic table
12how can you calculate the number if neutrons in an atom?
mass number - atomic number
13Why do atoms have no overall charge?
equal numbers if positive protons and negative electrons
14How many electrons would you place in the first, second and third shell?
up to 2 in the first shell and up to 8 in the second and third shells
15what is an element?
substance made of one type of atom
16what is a compound?
substance made if more than one type of atom chemically bonded together
17what is a mixture?
two or more substances not chemically combined
18what are isotopes?
atoms of the same element(same number of protons) with different numbers of neutrons
19what are the four physical processes that can be used to separate mixtures?
filtration, crystallisation, distillation, fractional distillation and chromatography
20what is relative mass?
the average mass of all the atoms of an element